Subnet Basics

IP Address Classifications

IP addresses contain 32 bits. There are several classifications of networks.

Class A Network is used for very large networks only. It uses 7 bits to define 127 networks and 24 bits to hold as many as 16,777,214 hosts. All Class A networks are in use, by companies such as General Electric and IBM.

Class B networks are used for medium sized networks only. It uses 14 bits to define 16,384 networks and 16 bits to hold as many as 16,384 hosts. All Class B networks are in use, by companies such as Microsoft and Exxon.

Class C networks are used for small networks only. It uses 21 bits to define 2,097,152 networks, but each network can only have 254 hosts per network.